When consumers launder fabrics, they desire not only excellence in cleaning, they also seek to impart superior fabric care benefits. Such care effects can be exemplified by one or more of reduction of wrinkles benefits; removal of wrinkles benefits; prevention of wrinkles benefits; fabric softness benefits; fabric feel benefits; garment shape retention benefits; garment shape recovery benefits; elasticity benefits; ease of ironing benefits; perfume benefits; color care benefits; anti-abrasion benefits; anti-pilling benefits; or any combination thereof. Compositions which provide both cleaning and fabric care benefits, e.g., fabric softening benefits, are known as “2 in 1”-detergent compositions and/or as “softening through the wash”-compositions.
Over the last couple of decades, a significant increase in cleaning performance has been achieved by adding enzymes into detergent compositions. There are different sorts of enzymes available and suitable for incorporation into detergent compositions dependent on the nature of the stain(s) to be removed. Furthermore, dependent on the form of the detergent composition, being either a granular product or a liquid, enzyme-stabilizing systems are needed to prevent enzyme degradation. In liquid laundry detergent compositions, enzymes are typically stabilized either by organic or inorganic acids. A typical example for an organic acid would be short chain carboxylic acids, e.g., formic acid. A typical example of an inorganic acid would be boric acid. Furthermore, salts of these acids can also be used, such as alkali salts of boric acids, e.g. sodium borate and others.
Another development over the last couple of years relates to the means of enhancing additional fabric care benefits, which are different from pure fabric cleaning benefits. Examples of these additional fabric care benefits are, e.g., fabric softening benefits, and color care benefits. The common feature of these fabric care benefits is that a fabric care agent needs to be deposited to a fabric. Due to the wash and/or rinse conditions, the deposition characteristics of such agents is not very high so that the amount deposited is not very high. In order to enhance the deposition characteristics of such fabric care agents, deposition aids have been added to such compositions. Examples of deposition aids suitable to enhance the deposition of fabric care agents are for example, cationic compounds, such as poly-quaternized ammonium compounds and cationic polysaccharides, e.g, cationic guar gums.
In order to have both superior cleaning performance, and excellent fabric care performance, it is desirable to formulate detergent compositions which combine an enhanced cleaning effect, driven by incorporation of enzymes, and very good fabric care effect, driven by incorporation of deposition aids for additional fabric care agents. However, it has now been observed when formulating liquid laundry detergent compositions providing cleaning and additional fabric care benefits, like reduction of wrinkles benefits; removal of wrinkles benefits; prevention of wrinkles benefits; fabric softness benefits; fabric feel benefits; garment shape retention benefits; garment shape recovery benefits; elasticity benefits; ease of ironing benefits; perfume benefits; color care benefits; anti-abrasion benefits; anti-pilling benefits; or any combination thereof, that enzyme-containing detergent compositions which contain a boron-based enzyme-stabilization system, and a cationic deposition aid tend to encounter a stability problem. This stability problem appears in the formation of beads formed from interacting components. Such bead formation can, in turn, lead to a precipitation within the fully-formulated detergent product. It has been found that the precipitate consists of certain components of the composition. These components have been identified to be a complex of the boron-based enzyme-stabilization system, and the cationic deposition aid. The precipitate remains undissolved even after shaking or warming of the composition.
Without being bound by theory, it is believed that this stability problem occurs due to an incompatibility of the boron-based enzyme-stabilization system and the cationic deposition aid, such as cationic polysaccharide-based deposition aids, e.g., cationic guar gums. It is believed that the formation of beads occurs due to an interaction of the boron-based enzyme stabilizing system with the cationic polysaccharide-based deposition aid, for example, with the cationic guar gum. It is further believed that this interaction occurs because of the affinity of boron to oxygen which could indeed manifest it in a reaction between the cationic polysaccharide-based deposition aid containing many sources of oxygen, e.g., hydroxy groups, ether groups, and the boron-based enzyme-stabilizing system, for example, in a boric acid- and/or borate-containing enzyme-stabilizing system. Without being bound by theory, it is believed that this interaction mainly takes place between oxygen atoms of two cis-orientated hydroxy groups (i.e., 1,2-cis-hydroxy groups) of the guar gum saccharide moiety and the boron atom.
The consequence of this bead formation is a drastic loss in fabric care performance, because the guar gum molecules which are then bound to the boron-based enzyme stabilizing system are not available to work as a deposition aid any more. Another consequence may be a loss in fabric cleaning performance occurred due to degradation of enzymes which aren't stabilized sufficiently any more, since the boron-based stabilizing system interacting with the guar gum does not suitable function as a enzyme stabilizer any more.
The present invention overcomes such incompatibility problems of cationic polysaccharide-based deposition aids, for example, cationic guar gums, and boron-based, for example, boric acid- and/or borate-containing, enzyme stabilizing systems. It is therefore an object of the present invention to provide liquid laundry detergent compositions comprising enzymes, suitable enzyme-stabilizing systems based on boron compounds like boric acid and/or borate which do not exhibit interaction with cationic polysaccharide-based deposition aids such as cationic guar gums. Another object of the present invention is to secure superior fabric cleaning and superior fabric care.
One embodiment of the present invention is a liquid laundry detergent composition comprising (a) at least one surfactant; (b) at least one enzyme and a boron-based enzyme stabilizing system comprising, for example, boric acid and/or salts thereof; (c) at least one fabric care ingredient which is not a fabric cleaning ingredient; and (d) at least one cationic polysaccharide-based deposition aid for the fabric care ingredient, wherein the cationic deposition aid does not exhibit interaction with the boron-based enzyme stabilizing system to provide both excellent fabric cleaning and superior fabric care.
It has now surprisingly been found that the incompatibility of the boron-based, for example, boric acid- and/or borate-containing, enzyme stabilizing systems and polysaccharide-based guar gums can be avoided when the interaction between these two groups is prevented. This can be achieved by modification of the polysaccharide-based deposition aid, for example, of the guar gum. By modification it is meant that the hydroxy groups of such cationic guar gums are substituted with chemical groups so that the interaction with a boron-based enzyme-stabilization system is prevented.